Sydney researchers develop new low-cost and safe plasma tech

The technology developed at the University of Sydney can dim the screens of electronic devices for a fraction of the cost of the current material that is used.

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The University of Sydney has announced the development of a low-cost, sustainable, and readily available technology its researchers say can, for example, dim the screens of electronic devices for a fraction of the cost of current tech.

A team led by researchers, including Dr Behnam Akhavan from the university, explained the breakthrough would replace indium, which is a rare chemical element widely used in devices such as smartphones and computers, windscreen glass, and self-dimming windows.

"Although small amounts are used to manufacture smart device screens, indium is expensive as it is hard to source; it naturally occurs only in small deposits," the researchers explained. "Industrial indium is often made as a byproduct of zinc mining, which means a shortage could occur if demand for optoelectronic devices -- such as LCDs and touch panels -- ramps up."

Akhavan, an ARC DECRA Fellow from the School of Biomedical Engineering, School of Physics and the Sydney Nanoscience Hub at the university, has developed a plasma-generated, hybrid nanocomposite material to use in its place.

The material is free of indium and according to the university, offers a low-cost, accessible, and environmentally sound electrochromic technology that allows glass to be dimmed at the push of a button or touch of a screen.

The plasma-generated material is composed of tungsten oxide and silver and can be applied to coat almost any solid surface, including flexible plastics.

As explained in research published in Solar Energy Materials and Solar Cells, plasma is created by adding energy to gas. Plasma is used most commonly in fluorescent light bulbs, neon signs, and some television and computer screens.

"When you change the transparency of a wearable electronic or a smart window, an electrochromic device is doing the work," Akhavan said.

"Until now, these devices have typically relied on materials like rare indium to do the job. What we have created is a manufacturer's dream: a technology that removes the need for indium and instead uses a plasma-engineered, three-layered structure that is much cheaper to produce."

The university said while early iterations of the tech were produced for the first time in 2019, it used a method of tungsten oxide deposition known as HiPIMS, now instead of a bare tungsten oxide layer, the group has developed a nanocomposite of tungsten oxide and silver.

"This nanotechnology-enabled approach allows electrochromic devices to efficiently and rapidly change colour upon a user's request," the university said.

The research explained the plasma coatings are transparent and also electrically conductive, made up of a layer of silver that is approximately 10,000 times thinner than the width of human hair, placed in between two nano-thin layers of tungsten oxide decorated with silver nanoparticles.

"These plasma-fabricated coatings can then be applied to electronic papers, smart phones and glass windows, and can be dimmed with the application of a small electrical current," Akhavan added.

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